Help please!

hello i am new to all this hacking and stuff and was just wondering if someone out there could help me...
my ipod touch is on the 1.1.1 firmware. i have jailbroken it and have installer installed. i was wondering if i update my ipod to the new firmware from itunes if i will lose all of my music etc... also how do you update installer? i want to get GBA games on my ipod touch but can not find iShare on the installer list and believe it is because it is the older version... please help! thanks!

thanks. do u know why i can not find iShare on installer? it is supposed to be under "Productivity". i need to download it so i can get the GBA ROMs and have tried everything i can think of... i found the website where i can download it on the computer but dont know how to get it onto my ipod lol. thanks again!

1. iTunes will offer to backup your music if you restore. If you're worried, back it up manually.
2. Installer can be updated through the application itself. If there's any available Installer updates, you'll find them under the Updates tab.
3. GBA Roms from iShare can be placed on your iPod touch by using SSH.